The invention relates to measuring of three-dimensional (3D) properties.
A distance measuring apparatus can be a range finder based on a time-of-flight principle, e.g. using a pulsed laser beam. A laser of the measuring apparatus having a suitable optical arrangement transmits an optical beam towards a desired object. The optical beam is reflected from the object to a receiver or detector that has a suitable optical arrangement for receiving. The duration for the optical beam to travel from the measuring apparatus to the object and back can be measured and the measured result can be transformed into distance on the basis of the speed of light.
One use of distance measurement is to measure the wear of the linings of metallurgical vessels, including, but not limited to, converter or ladle linings. In this context, knowledge of the thickness of the refractory lining—also called “remaining refractory thickness”—permits effective utilization of the refractory lining up to the wear limit without an increased risk of blow-out of the metallic jacket of the metallurgical vessel. Additionally, being able to measure the wear of these linings makes it possible to optimize the service life of the vessel and to prevent excessive wear.
Linings of converters must be renewed relatively often, as their life time varies from a week to several months, depending on what is melted, the material of which the lining is made, and the number of melts for which the vessel is used.
By deflecting (scanning) the laser beam in two directions one can determine the measured distance and polar co-ordinate angles of each point where the optical beam hits the object's surface, e.g. a vessel's inner surface. These measured points define the wear profile of the lining, which may be output for instance to a display terminal, by which the wear profile measured from a metallurgical vessel in use can be compared graphically and numerically with the profile that was measured of the inner surface of the same vessel during the modelling step before the vessel was actually brought into use, i.e. before the first melt.